A Morphological Study of the Papillary Muscles of the Heart, through Cadaveric Dissection

Abstract

Background: Papillary muscles are important structures in the ventricles of the heart that work with the chordae tendineae to support the atrioventricular valves and prevent backward flow of blood during contraction. They differ in number, size, and arrangement between the right and left ventricles, reflecting the different functional demands of each side of the heart. The aim of this study was to evaluate the morphological features of the papillary muscles of the heart in a Nigerian population, through cadaveric dissection. Methodology: A cross-sectional descriptive study was conducted using 23 adult Nigerian cadavers preserved in formalin, all without evidence of cardiac trauma or deformity. The hearts were carefully dissected to expose the papillary muscles for detailed examination. Their morphological features were assessed, and shapes were classified as conical, pyramidal, fan-shaped, or broad. In addition, observed papillary muscle patterns included small projections, separated base with a fused apex, a single base with a divided apex, large papillary formations, and large bridge configurations. Results: The shapes of the papillary muscles observed were conical shape, fan-shape, broad shape and pyramid shape. The noted papillary muscle patterns were large bridge, large papillary, single base with divided apex, separated base with fused apex, and small projection patterns. The conical shape was the most common (56.3%) in the anterior papillary muscles of the right ventricle, while broad shape was most observed (60%) in the posterior papillary muscles of right ventricule. Conical shape was prevalent (88.2%) in the septal right ventricular muscle. In the left ventricle, broad shape dominated (73.7%) in the anterior muscle and was common (50%) in the posterior muscles. The large bridge pattern dominates the left ventricle, while the separated base with fused apex dominated the right ventricle. Conclusion: The results of the study shows that the left ventricle is equipped with larger papillary muscles, than the right ventricle.  This is likely due to its heavier workload in pumping a higher volume of blood.